JP2008031847A - Gas turbine combustor, its operating method, and modification method of gas turbine combustor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a generation amount of dust under a low load condition of a gas turbine. <P>SOLUTION: The gas turbine combustor comprises: an inner cylinder mixing combustion air with fuel so as to generate combustion gas; a swirler 10 positioned upstream of the inner cylinder so as to give a swirl component to the combustion air flowing into the inner cylinder; and a combustion chamber arranged in the inner cylinder so as to burn the fuel and the air. A pressure spraying type fuel nozzle 9 is arranged in the center of the axis of the swirler, and has a pilot injection hole blowing pilot fuel and a main injection hole blowing main fuel and arranged on an outer peripheral side of the pilot injection hole, and a means for supplying water to the pilot fuel or main fuel is provided. Therefore, the generation amount of dust is suppressed under the low load condition of the gas turbine. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas turbine combustor, an operation method thereof, and a gas turbine combustor remodeling method.

  In an oil fuel-fired combustor, oil fuel is atomized by a fuel nozzle, and combustion is promoted by promoting mixing of small diameter fuel droplet groups and combustion air. There are an air spray type and a pressure spray type as a fuel nozzle spraying method.

  Among these, the pressure spray type fuel nozzle sprays and atomizes oil fuel at a high speed, so that atomization is impaired when the spray speed of the oil fuel decreases. For this reason, atomization is not promoted when the fuel flow rate is low and the spraying speed is lowered as in the ignition condition of the combustor. Therefore, there is a possibility of causing an ignition failure and an increase in emission of colored smoke accompanying it.

  As a fuel nozzle for solving such a problem, there is one described in Japanese Patent Publication No. 7-62522. The fuel nozzle includes a primary fuel nozzle that swirls the oil fuel at the center of the axis of the fuel nozzle, and a secondary fuel nozzle that is located on the outer periphery of the fuel nozzle and swirls the oil fuel in the same manner as the primary fuel nozzle. A dual orifice type fuel nozzle having a fuel nozzle.

  The characteristic of the dual orifice type fuel nozzle is that the fuel is ejected from the primary fuel nozzle having a small nozzle hole diameter under low flow conditions such as ignition, so that the supply pressure of the oil fuel can be secured and the atomization performance is not impaired. In addition, oil fuel can be ejected from a secondary fuel nozzle having a large nozzle hole diameter under high load conditions where the flow rate increases, so that fine particles can be produced over a wide range from startup to high load conditions without excessively increasing the supply pressure. It is possible to spray fuel with excellent performance.

Japanese Patent Publication No. 7-62522

  By making the pressure spray type fuel nozzle a dual orifice type, fuel can be sprayed only from the primary fuel nozzle under ignition conditions, and the fuel supply pressure necessary for atomization can be ensured. In a high load condition in which the fuel flow rate increases, oil fuel can also be ejected from the secondary fuel nozzle to prevent an excessive increase in supply pressure.

  However, in general, a pressure spray type nozzle has lower atomization performance of fuel droplets than an air spray type fuel nozzle. In particular, under the low load condition of the gas turbine where the fuel starts to be ejected from the secondary fuel nozzle, the fuel supply pressure of the secondary fuel nozzle is low, so that the atomization of fuel droplets is impaired.

  If atomization of the fuel droplets is impaired, the fuel droplets become large and the possibility of generating dust increases. Under low load conditions where fuel starts to be ejected from the secondary fuel nozzle, the combustion temperature is low and it is difficult to completely eliminate the soot and dust.

  Therefore, an object of the present invention is to suppress the generation amount of soot under low load conditions of a gas turbine.

  The present invention is characterized in that means for supplying water to the fuel pipe of the fuel nozzle is provided.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to suppress the generation amount of dust in the low load conditions of a gas turbine.

  Generally, in an oil fuel-fired combustor, oil fuel is atomized by a fuel nozzle, and combustion is promoted by promoting mixing of small-diameter fuel droplet groups and combustion air. As a fuel nozzle for atomizing oil fuel, there is an air spray type that uses high-pressure atomizing air or the like to atomize the air using the shearing force of air. However, this method requires a high-pressure air source and auxiliary equipment accompanying it, and there is a problem that the initial cost increases. In addition, when extracting high-pressure atomized air that atomizes fuel from a compressor of a gas turbine, it is necessary to boost or cool the extracted air. There is a possibility of reducing the efficiency of the entire turbine.

  On the other hand, as a fuel nozzle that does not use high-pressure spray air, there is a pressure spray type fuel nozzle. The pressure spray type fuel nozzle is a fuel nozzle that increases the supply pressure of oil fuel and accelerates the spraying speed of the fuel to atomize the fuel. The use of a pressure spray type fuel nozzle eliminates the need for a compressor for atomizing air and an auxiliary device associated therewith. Therefore, there is an advantage that the initial cost and running cost can be reduced and the efficiency of the gas turbine is not lowered.

  However, in general, a pressure spray type nozzle has lower atomization performance of fuel droplets than an air spray type fuel nozzle. This tendency is the same for the dual orifice type fuel nozzle described in Japanese Patent Publication No. 7-62522. In particular, under the low load condition of the gas turbine where the fuel starts to be ejected from the secondary fuel nozzle, the fuel supply pressure of the secondary fuel nozzle is low, so that the atomization of fuel droplets is impaired.

  And as a 1st subject of the gas turbine provided with the oil burning combustor which applies this invention, there exists a reduction of the dust in gas turbine exhaust gas. Soot generated in an oil-fired combustor is likely to be generated when fuel droplets are large and mixing with combustion air is poor. On the other hand, most of the dust generated from the oil-fired combustor has the property of burning and disappearing when exposed to high-temperature gas. Therefore, atomization is promoted because the fuel flow to be sprayed is high and the supply pressure is high under the high load condition of the gas turbine, and soot generated due to the high combustion temperature is burned and disappears.

  On the other hand, as described above, since the fuel supply amount to be sprayed is small under the low load condition, the supply pressure becomes low, and atomization of the fuel droplets sprayed from the fuel nozzle is not promoted, and large droplets are sprayed. Furthermore, the combustion gas temperature is low under low load conditions, and the generated soot particles cannot be completely combusted. Therefore, if no measures are taken, a large amount of soot may be discharged out of the system together with the exhaust gas. is there.

  Further, as a second problem of the gas turbine provided with the oil-fired combustor, there is a reduction in emission amount of nitrogen oxides (NOx). As a general method for reducing nitrogen oxide in an oil-fired combustor, water or steam is sprayed from a water spray nozzle to a combustion field to lower the local flame temperature, and thermal NOx generated from a high temperature combustion region is reduced. The method of reducing is adopted. However, there is a problem that the efficiency of the gas turbine is reduced by spraying water.

  Hereinafter, embodiments of a gas turbine combustor using the present invention, a method for operating the gas turbine combustor, and a method for modifying the gas turbine combustor will be described with reference to the drawings.

  Example 1 of the present invention will be described below. FIG. 1 is a schematic configuration diagram illustrating an overall configuration of a gas turbine plant. As shown in FIG. 1, a gas turbine plant mainly combusts a compressor 1 that compresses air to generate high-pressure combustion air, and combustion air 13 introduced from the compressor 1 and fuel. A combustor 3 that generates a gas 14 and a gas turbine 2 into which the combustion gas 14 generated by the combustor 3 is introduced. Note that the shafts of the compressor 1 and the gas turbine 2 are connected.

  The combustor 3 includes an inner cylinder 7 that generates combustion gas, a fuel nozzle 9 that sprays fuel, a swirler 10 that imparts swirl to the combustion air 13, and a spark plug 11, and an outer cylinder 5 and an end cover 6. It is a pressure vessel sealed with. A fuel nozzle 9 for spraying fuel is disposed on the upstream side of the axial center position of the inner cylinder 7, a swirler 10 for holding a diffusion flame 15 is installed around the nozzle, and an inner cylinder cap is disposed on the outer periphery thereof. 12 is provided.

  According to the present embodiment configured as described above, the combustion air 13 from the compressor 1 passes through the annular air flow path constituted by the outer cylinder 5 and the inner cylinder 7 to the inner cylinder 7 and the inner cylinder cap 12. It is introduced into the inner cylinder 7 from the provided combustion holes, cooling holes, and swirler 10. The air supplied to the inner cylinder 7 is mixed with fuel, and this mixed gas is ignited by the spark plug 11 and burns inside the inner cylinder 7. The combustion gas 14 generated by the combustion is supplied to the gas turbine 2 via the transition piece 8 to drive the gas turbine 2. Thereby, the generator 4 connected to the gas turbine 2 is driven to generate power.

  The fuel supply system 16 is a fuel supply device 17 including a fuel tank, an oil pump, a pressure regulator, a fuel cutoff valve, a fuel flow meter, and the like, and a distributor that distributes fuel to a plurality of combustors installed downstream of the fuel supply device 17. 18 and a fuel pipe 19 and the like.

  In this embodiment, a plurality of water spray nozzles 20 for spraying water on the combustion field are installed on the end cover 6 at a position facing the swirler 10. The end cover 6 is formed with a manifold 21 for supplying water to a plurality of water spray nozzles 20. Water is supplied from the water supply system 22 to the manifold 21, and water is sprayed from the plurality of water spray nozzles 20. A water supply system 22 for supplying water to the water spray nozzle 20 includes a water supply device 23 such as a water pump, a pressure regulator, a water flow meter, a water pipe 24, and the like.

  In the combustor of the gas turbine configured as described above, in the first embodiment, means for supplying water to the fuel pipe of the fuel nozzle 9 is installed. As this means, it is possible to connect a pipe for supplying water vapor to the fuel. In this embodiment, a water supply system 25 is connected to the fuel pipe as the means, and the water supply system 25 includes a water supply device 26 including a water pump, a pressure regulator, a water flow meter, a water pipe 27, and the like. .

  Here, the main purpose of spraying water onto the combustion field from the water spray nozzle 20 is to reduce the emission amount of nitrogen oxides (NOx) in the exhaust gas that causes air pollution. The purpose of supplying water to the fuel nozzle 9 is to reduce the emission of soot contained in the exhaust gas in addition to the reduction of the emission of nitrogen oxides (NOx).

FIG. 2 shows details of the fuel supply system 16, the atomizing air supply system 39 and the water supply system 25 connected to the fuel nozzle 9. The fuel nozzle 9 of this embodiment is a pressure spray type dual orifice type. Fuel is supplied only to the pilot flow path 30 under conditions where the fuel flow rate is low, such as during ignition, and fuel is supplied to the main flow path 31 under conditions where there is a high fuel flow rate, such as during high loads, thereby increasing the fuel supply pressure. It has a structure that prevents the rise. A pressurizing valve 32 is installed on the downstream side of the main flow path 31. A main flow path 31 and a pilot flow path 30 are connected to a distribution pipe 33 upstream of the pressurization valve 32. Further, a fuel pipe 19 from the fuel supply device 17 is connected upstream of the distribution pipe 33, and a check valve 34 is provided in the fuel pipe 19.

  Here, the pressurization valve 32 installed in the main flow path 31 is a check valve that can set the pressure at which fuel starts to flow in the forward direction when the forward pressure acts on the pressurization valve 32. At the following pressure, the fuel is prevented from flowing into the main nozzle hole.

  The other end of the distribution pipe 33 is connected to an atomizing air pipe 35 that supplies air to the pilot flow path 30. An atomizing air pipe 36 that supplies air also to the main flow path 31 is connected to the downstream side of the pressurization valve 32 provided in the main flow path 31. Check valves 37 and 38 are installed in the respective spray air pipes 35 and 36, and the spray air is supplied to the pilot flow path 30 and the main flow path 31 by the spray air supply system 39. The atomizing air supply system 39 includes an atomizing air supply device 40 and an atomizing air pipe 41 and is branched from the atomizing air pipe 41 and connected to the atomizing air pipes 35 and 36.

On the other hand, in order to supply water to the fuel nozzle 9, the water pipe 27 from the water supply device 26 is between the distribution pipe 33 and the check valve 34, and the check valve 28 is provided upstream of the pressurizing valve 32. Connected through.

  Next, the outline | summary of operation | movement of the fuel supply system 16, the spray air supply system 39, and the water supply system 25 of the fuel nozzle 9 is demonstrated. The fuel supplied from the fuel supply device 17 is distributed to each combustor by the distributor 18 and guided to the distribution pipe 33 through the check valve 34. The check valve 34 is a valve for preventing combustion air, combustion gas, and the like from flowing back to the fuel supply system 16. The fuel supplied to the distribution pipe 33 is distributed to the pilot flow path 30 and the main flow path 31. Under conditions where the fuel flow rate is low, such as during ignition, the supply pressure of the fuel acting on the pressurization valve 32 installed in the middle of the main flow path 31 is lower than the set pressure of the pressurization valve 32, so the pressurization valve 32 can be opened. The fuel is supplied only to the pilot flow path 30. After the ignition of the gas turbine, when the flow rate of fuel supplied to the fuel nozzle increases as the turbine speed increases and the load of the gas turbine increases, the fuel supply pressure acting on the pressurizing valve 32 increases. Then, the fuel is supplied to the main channel 31 in addition to the pilot channel 30 by pushing the pressurizing valve 32 open.

  In this way, at the time of ignition, fuel can be supplied only to the pilot flow path 30 connected to the pilot nozzle hole having a small fuel nozzle diameter, and supply pressure necessary for atomization of the fuel can be ensured even with a small fuel flow rate. Can do. Therefore, fuel droplets can be atomized and the ignition characteristics of the combustor are improved. Further, during the load operation, the pressurization valve 32 is opened, and fuel is supplied to the main flow path 31 connected to the main nozzle hole, so that it is possible to prevent an excessive increase in the fuel supply pressure.

  Next, an outline of the operation of each system when the gas turbine is stopped will be described. The internal temperature of the combustor 3 operating in a high temperature state is maintained at a high temperature for a long time after the gas turbine is stopped. When the fuel nozzle 9 is exposed under this condition, the fuel nozzle 9 is heated, the fuel remaining inside the fuel nozzle is heated and carbonized, and the fuel ejection portion of the fuel nozzle 9 and coking that adheres to the inside are generated. To do. When coking occurs, the fuel injection hole may be blocked and fuel may not be injected.

  For this reason, in general, an oil fuel-fired combustor is provided with means for supplying atomized air or the like to the flow path of the fuel nozzle for the purpose of discharging the fuel remaining inside the fuel nozzle to the outside of the system. Yes. Also in the present embodiment, means for supplying spray air for the same purpose is provided. After the gas turbine is stopped, the air discharged from the atomizing air supply device 40 is branched from the air pipe 41 to the pilot atomizing air pipe 35 and the main atomizing air pipe 36, and each flow path is passed through the check valves 37 and 38. To be supplied.

  Further, when the fuel nozzle 9 is ignited in this embodiment, fuel is supplied only to the pilot flow path 30 and no fuel is supplied to the main flow path 31. Therefore, by supplying air to the main flow path 31, atomization of the fuel ejected from the pilot flow path 30 can be assisted by the air ejected from the main flow path 31, and the fuel droplet fine particles at the time of ignition It is possible to improve the ignition characteristics.

  In the first embodiment according to the present invention, water is supplied through the check valve 28 from the means for supplying water between the distribution pipe 33 and the check valve 34 of the fuel nozzle 9 shown in FIG.

  The pressure spray type dual orifice type fuel nozzle to which the present invention is applied may have a large particle size of sprayed fuel droplets when the fuel supply pressure is low. In the present embodiment, atomization of fuel droplets during ignition is promoted using the action of the pressurizing valve 32 and air from the main flow path. However, under the low load condition of the gas turbine in which the fuel supply pressure rises and the pressurization valve 32 begins to open, the supply pressure of the main flow path 31 is low, so the droplet diameter sprayed from the main flow path 31 tends to increase. .

  The “low load condition of the gas turbine” in the present embodiment refers to the operating state of the gas turbine other than the load condition during the rated operation. Therefore, the “low load condition of the gas turbine” includes not only the load operation state but also the state where the gas turbine is ignited / accelerated. The “load condition during rated operation” refers to a load condition designed so that the atomization performance of fuel droplets is maximized in the main nozzle hole of the main flow path 31.

  When the diameter of the fuel droplets supplied to the combustor is large, the mixing of fuel and air is impaired and the oxidation reaction is delayed, so that the generation of soot is promoted. Further, since the fuel droplet diameter is large, the generated soot particles are enlarged, and the amount of soot contained in the exhaust gas may increase.

  For this reason, in this embodiment, water is supplied from the water supply device 26 which is means for supplying water to the fuel pipe of the fuel nozzle 9 under the low load condition of the gas turbine in which the fuel supply pressure of the main flow path 31 is low. And the supply pressure of the main flow path 31 is increased, and atomization of the fuel and water droplets ejected from the main flow path 31 is promoted.

Water flowing into the fuel pipe of the fuel nozzle is distributed to the pilot flow path 30 and the main flow path 31 by the distribution pipe 33, and the oil fuel and water are mixed and sprayed on the combustion field in each flow path. The evaporation temperature of water is lower than the temperature of the combustion field, and the water sprayed on the high temperature combustion field evaporates explosively. For this reason, atomization of the fuel droplets can be expected due to the impact generated when the water droplets explode, and the mixing of the atomized fuel droplets and the combustion air is promoted, and the enlargement of the soot particles can be prevented. As a result, the amount of dust in the exhaust gas can be reduced.

  Further, when water droplets and fuel droplets are mixed and sprayed on the combustion field, many OH radicals are generated by evaporation and thermal decomposition of the water droplets. Since this OH radical is adsorbed and oxidized on polycyclic aromatic hydrocarbons to suppress the generation of soot, when water droplets and fuel droplets are mixed and sprayed on the combustion field, soot generation is effectively suppressed. Is possible.

  Further, in this embodiment, since water droplets and fuel droplets are mixed and sprayed on the combustion field, the sprayed water droplets can effectively lower the flame temperature and prevent local flame temperature rise. Can do. Therefore, it becomes possible to effectively suppress the discharge amount of nitrogen oxide (NOx) generated from the high temperature flame region.

  The water spray from the water spray nozzle 20 is effective in suppressing the generation of OH radicals due to thermal decomposition after the water droplets have evaporated and the effect of reducing the flame temperature and suppressing the discharge of nitrogen oxides (NOx) by water spray. Can also be obtained. However, by supplying water directly to the fuel supply system of the fuel nozzle 9 as in this embodiment, water and oil are mixed inside the fuel nozzle, and when sprayed on the combustion field, water droplets and fuel droplets are mixed. Therefore, those effects become more remarkable than when water is sprayed on the combustion field by the water spray nozzle 20.

  Next, a method for controlling the water supplied to the fuel nozzle 9 will be described. FIG. 3 is a schematic diagram showing the relationship between the operating state of the gas turbine when water is not supplied to the fuel nozzle 9 and the supply pressure of each flow path in the fuel nozzle 9 as a comparative example. A broken line ABC indicates a change in the supply pressure of the pilot flow path 30, and a solid line DE indicates a change in the supply pressure of the main flow path 31.

  When the fuel is supplied to the fuel nozzle 9, the fuel flows into the pilot flow path 30 by the action of the pressurizing valve 32, so that the supply pressure of the pilot flow path 30 increases from A to B. Point B is a set pressure of the pressurizing valve 32. When the supply pressure exceeds the point B, fuel starts to flow from the point D to the main flow path 31 and the supply pressure increases. The supply pressure of the main flow path increases from D to E depending on the operating state of the gas turbine. On the other hand, since the fuel injection hole of the main channel 31 is large, the supply pressure of the main channel 31 is low under low load conditions, and atomization of the sprayed droplets cannot be promoted. This is one of the factors that generate dust under the low gas turbine load condition shown in FIG.

  FIG. 4 shows a change in the supply pressure of the main flow path 31 when water is supplied to the fuel nozzle 9 in the case of the first embodiment. In the example shown in FIG. 4, water is supplied to the fuel nozzle 9 from the point F at which the load operation is started, and the supply pressure is increased to the point G. In general, since a diffusion oil-fired combustor is excellent in combustion stability, the combustion state is kept stable even when water equivalent to fuel is sprayed. By supplying water to the fuel nozzle 9, the supply pressure of the main flow path 31 rises from the F point to the G point, so that atomization of water droplets and fuel droplets sprayed from the fuel nozzle 9 is promoted. As the load increases, the fuel flow rate increases and the supply pressure of the main flow path 31 increases. At this time, since the supply amount of water is also increased, the supply pressure of the main flow path 31 can be increased to the H point corresponding to almost twice the pressure at the point I where only oil fuel is supplied. Further, atomization of water droplets and fuel droplets is further promoted.

  In the embodiment shown in FIG. 4, water is supplied up to the upper limit of the discharge pressure of the oil pump when the supply pressure of the main flow path 31 is the upper limit. When the supply pressure of the main flow path 31 reaches the upper limit value of the discharge pressure of the oil pump at the point H, no more fuel can be supplied. Therefore, the flow rate of the supplied water is reduced from the H point as the fuel flow rate increases, and finally the water supply to the fuel nozzle is stopped at the E point so that only fuel is ejected from the fuel nozzle. It is a thing. Therefore, since the fuel supply pressure is the fuel nozzle design condition at the point E in the rated operation state, the spray characteristics of the fuel nozzle set in advance can be reproduced.

  Further, at the point H where the flow rate of water supplied to the fuel nozzle 9 starts to decrease, the temperature of the combustion gas is high, so even if soot is generated, it is burned out in the combustion chamber. Therefore, even if the amount of water supplied is reduced, the amount of generated dust does not increase.

  Further, the flow rate of spraying water on the combustion field is determined by the operating state of the gas turbine and the like. Therefore, when the flow rate of water that can be supplied to the fuel nozzle 9 is smaller than the flow rate of water that should be supplied to the combustion field, the flow rate of the difference can be sprayed from the water spray nozzle 20. That is, in Example 1, the flow rate of water supplied to the fuel nozzle 9 from the point H in FIG. 4 decreases, but the load of the gas turbine increases, so the total flow rate of water sprayed to the combustion field increases. Therefore, it is possible to suppress the discharge amount of nitrogen oxide (NOx) by spraying from the water spray nozzle 20 the decreased amount of water sprayed from the fuel nozzle 9 and the increased amount of water flow accompanying the increase in gas turbine load. It becomes.

  In FIG. 4, the timing for starting the supply of water to the main flow path 31 is the point F at which the load operation of the gas turbine is started. However, the timing for starting the supply of water to the main flow path 31 is not limited to the point F at which the load operation of the gas turbine is started, and may be a point D at which the supply of fuel to the main flow path 31 is started. Even when starting from point D, which is a low-load condition of the gas turbine, atomization of water droplets and fuel droplets is promoted as in this embodiment, and the amount of nitrogen oxides discharged can be reduced. However, by supplying water in the section FI where dust is generated and setting the supply pressure of the main flow path to the section GH, dust can be reduced most efficiently while suppressing the amount of water used.

  Further, the means for supplying water to the fuel pipe of the fuel nozzle described in this embodiment is also useful when added to an existing gas turbine combustor. In a gas turbine combustor that already employs a dual orifice type combustor, it is possible to obtain the same effect as in this embodiment by adding a water supply system 25 as means for supplying water to the fuel pipe of the fuel nozzle. is there.

  A second embodiment will be described with reference to FIGS. In the second embodiment, as shown in FIG. 5, a check valve 45 is installed in the pilot flow path 30 connected to the distribution pipe 33, and the water supply pipe 46 from the water supply device 26 is connected to the pilot flow path 33 downstream thereof. , Connected via a check valve 47. Other components are the same as those in the first embodiment.

  Water from the water supply device 26 is supplied to the pilot flow path 30 downstream of the check valve 45. Therefore, the water supplied to the pilot flow path 30 does not flow into the distribution pipe 33, that is, the main flow path 31 by the action of the check valve 45. Further, when water is supplied to the pilot flow path 30 by the water supply device 26, if the oil supply pressure supplied from the fuel supply device 17 is lower than the supply pressure of the pilot flow path 30 at the position of the distribution pipe 33, the fuel is main. It flows only in the flow path 31. When it is higher than the pilot flow path 30, part of the fuel is mixed into the pilot flow path 30 and ejected from the pilot flow path 30.

  FIG. 6 is a detailed view of the tip of the fuel nozzle 9 (A portion in FIG. 5). The fuel nozzle 9 includes a nozzle body 50, a nozzle cap 51, a main chip 52, and a pilot chip 53. The fuel from the pilot flow path 30 is given a swirl force in a swirl chamber 54 inside the pilot tip 53 and becomes a pilot spray 56 from the pilot injection hole 55 and sprays to the combustion field. The fuel from the main flow path 31 is given a swirl force in a swirl chamber 57 composed of a main tip 52 and a nozzle cap 51 and becomes a main spray 59 from the main injection hole 58 and sprays to the combustion field.

  Although the spray characteristics such as the spray angle of the fuel nozzle can be controlled by the structure of the fuel nozzle, the second embodiment is an example in which the pilot spray 56 is controlled to be inside the main spray 59.

  Therefore, as shown in FIG. 4, when water is supplied to the fuel nozzle 9 according to the second embodiment at the point F where the load operation of the gas turbine starts and the generation amount of dust increases, the load of the gas turbine is reduced and the fuel supply amount is reduced. Therefore, the fuel supply pressure of the distribution pipe 33 is lower than the water supply pressure of the pilot flow path 30. The fuel flows only in the main flow path 32, and the water from the water supply device 26 flows only in the pilot flow path 30. Accordingly, the pilot spray 56 is sprayed with only water droplets, and the main spray 59 is sprayed with only fuel. Since the nozzle hole diameter of the pilot nozzle 55 is small, when the amount of water spray required in the gas turbine operation state at point F cannot be supplied only from the pilot nozzle 55, water is sprayed from the water spray nozzle 20 installed on the end cover 6. Is possible.

In this embodiment, since there is a pilot spray 56 of only water droplets inside the flame formed by the main spray 59 of fuel only, nitrogen oxide (NOx) is discharged by the action of the water droplets sprayed inside the flame. The temperature of the encouraging high temperature circulation region can be effectively reduced. Therefore, in Example 1 in which water is sprayed from the water spray nozzle 20, it is possible to more effectively reduce the discharge amount of nitrogen oxides (NOx) in addition to the effect of suppressing soot generation.

A third embodiment will be described with reference to FIG. In the third embodiment, the water pipe 27 of the first embodiment is branched into a water pipe 60 and a water pipe 61 downstream of the check valve 28, and the water pipe 60 is connected between the distribution pipe 33 and the check valve 34, The pipe 61 is connected downstream of the check valve 45 in the pilot flow path 30.

  In the case of the third embodiment, when the water supply pressure is higher than the fuel supply pressure, only water is supplied to the pilot channel 30 and water is mixed into the main channel from the water pipe 60. Is supplied. Therefore, the pilot spray 56 described with reference to FIG. 6 is only water droplets, and the main spray 59 is a spray in which fuel droplets and water droplets are mixed, and an effect equivalent to that of the second embodiment can be expected.

  In the third embodiment, since water is also supplied to the main flow path 31, an increase in supply pressure of the main flow path 31 is expected, and atomization of water droplets and fuel droplets sprayed from the main flow path 31 is promoted. Can be expected.

  Example 4 will be described with reference to FIG. In the fourth embodiment, a water supply pipe 72 from a water supply device 70 is installed in a spray air pipe 36 for supplying spray air to the main flow path 31 via a check valve 71, and other components are examples. Same as 1.

  The water supplied from the water supply device 70 to the main channel 31 does not flow back to the pilot channel 30 due to the action of the pressurizing valve 32. Further, the check valve 38 does not flow back to the atomizing air pipe 36 but is supplied only to the main flow path 31.

  As in the other embodiments, when water is supplied to the fuel nozzle from the state where the gas turbine starts the load operation, only the fuel droplets are sprayed in the pilot spray, and the water spray and fuel droplets are mixed in the main spray. Sprayed. Since only the fuel droplets are sprayed in the pilot spray, the stability of the flame formed from the pilot spray is improved, and more water can be supplied as compared to the other embodiments. , 3 can be expected to suppress the emission of dust and nitrogen oxides (NOx) equal to or higher than 3.

  It can be widely applied to a combustion apparatus equipped with a pressure spray type oil fuel nozzle.

1 is a diagram illustrating an overall configuration of a gas turbine in Embodiment 1. FIG. 2 is a diagram illustrating each supply system of a pressure spray type fuel nozzle in Embodiment 1. FIG. It is a figure in the case of a comparative example about the supply pressure of a fuel nozzle in the rated load conditions from starting of a gas turbine plant. It is a figure in the case of Example 1 in a rated load condition after starting of a gas turbine plant. FIG. 4 is a diagram illustrating each supply system of a pressure spray type fuel nozzle according to a second embodiment. It is a figure showing the detailed structure of a fuel nozzle front-end | tip part. FIG. 6 is a diagram illustrating each supply system of a pressure spray type fuel nozzle according to a third embodiment. FIG. 6 is a diagram illustrating each supply system of a pressure spray type fuel nozzle according to a fourth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Gas turbine, 3 ... Combustor, 4 ... Generator, 5 ... Outer cylinder, 6 ... End cover, 7 ... Inner cylinder, 8 ... Transition piece, 9 ... Fuel nozzle, 10 ... Swivel machine, DESCRIPTION OF SYMBOLS 11 ... Spark plug, 12 ... Inner cylinder cap, 13 ... Combustion air, 14 ... Combustion gas, 15 ... Diffusion flame, 17 ... Fuel supply device, 18 ... Distributor, 19 ... Fuel piping, 20 ... Water spray nozzle, 21 ... Manifold, 22, 25 ... water supply system, 23, 26 ... water supply device, 24, 27 ... water piping.

Claims (5)

A gas turbine combustor having an inner cylinder that mixes combustion air and fuel to generate combustion gas, and a fuel nozzle that supplies fuel to the inside of the inner cylinder,
A gas turbine combustor comprising means for supplying water to a fuel pipe of the fuel nozzle. An inner cylinder that mixes combustion air and fuel to generate combustion gas, a swirler that is located upstream of the inner cylinder and imparts a swirling component to the combustion air flowing into the inner cylinder, and a combustion chamber that burns fuel and air A gas turbine combustor provided inside the inner cylinder,
A pressure spray type fuel nozzle provided with a pilot nozzle for jetting pilot fuel and a main nozzle for jetting main fuel on the outer peripheral side of the pilot nozzle is provided at the center of the swirler,
A gas turbine combustor comprising means for supplying water to the pilot fuel or the main fuel. An inner cylinder that mixes combustion air and fuel to generate combustion gas, a swirler that is located upstream of the inner cylinder and imparts a swirling component to the combustion air flowing into the inner cylinder, and a combustion chamber that burns fuel and air A gas turbine combustor provided inside the inner cylinder,
A pressure spray type fuel nozzle provided with a pilot nozzle for jetting pilot fuel and a main nozzle for jetting main fuel on the outer peripheral side of the pilot nozzle is provided at the center of the swirler,
A pressurizing valve which is connected to the main nozzle hole and prevents a fuel having a predetermined pressure or less from flowing into the main nozzle hole into a main flow path to which fuel is supplied;
A gas turbine combustor comprising means for supplying water to the pilot fuel or the main fuel. An inner cylinder that mixes combustion air and fuel to generate combustion gas, and a fuel nozzle that is provided inside the inner cylinder and includes a pilot flow path for supplying pilot fuel and a main flow path for supplying main fuel are installed. A method for operating a gas turbine combustor, comprising:
Supplying fuel to the pilot channel or the main channel;
A method for operating a gas turbine combustor, wherein water is supplied to the pilot flow path or the main flow path. A gas turbine combustor remodeling method in which an inner cylinder that generates combustion gas by mixing combustion air and fuel and a fuel nozzle that supplies fuel to the inside of the inner cylinder are installed,
A gas turbine combustor remodeling method, characterized in that means for supplying water to the fuel pipe of the fuel nozzle is installed.

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